Sawmill dogs operated by a track above the log carriage



Oct. 4, 1955 A. J. PARENT 2,719,552

SAWMILL DOGS OPERATED BY A TRACK ABOVE THE LOG CARRIAGE Filed April 14, 1954 2 Sheets-Sheet l 39 4/ [72 0672 $073 A deZard :ZPa ran 15',

1955, A. J. PARENT 2,719,552

SAWMILL DOGS OPERATED BY A TRACK ABOVE THE} LOG CARRIAGE 2 Sheets-Sheet 2 Filed April 14, 1954 Inventor,

Adelard :Z Parent,

United States Patent SAWMILL DOGS'OPERATED BY A TRACK ABOVE THE LOG CARRIAGE Adelard J. Parent, South Berwick, Maine Application April 14, 1954,'Serial'No. 423,071

7 Claims. (Cl. 143-431) This invention relates generally to new and useful improvements in sawmills and more particularly to an improved operating mechanism for log gripping devices.

To fix the position of a log prior to each sawing operation in a sawmill, there is provided a log gripping device well known to those skilled in the art as a dog. To set the dog, that is to lower -it into a position of firm engagement with the log to be sawed, a hand operated crank and screw mechanism is usually provided. This mechanism has proven difficu'lt to operate because of the inconvenient location of the crank, as is required to prevent interference with the saw. It is also slow in operation, owing to the many cranking motions necessary for setting the dog.

Therefore, one object of this invention is to provide means whereby the setting of the dog in a sawmill may be accomplished more quickly and easily.

After the log has been partially sawed, the dog is then released, the log turned over and resecured for completion of the sawing operations. Subsequently, the dog is again released so that the remaining portion of the log may :be taken away. In both cases, the cranking required to release the dog in a conventional sawmill impedes rapid production, .and in the latter case, creates a considerable hazard as well, owing to the fact that the final release .is usually performed while the carriage supporting the remainder of the log is still in motion.

It is an other object .of this invention, therefore, to provide means whereby the dog in a sawmill maybe released more rapidly.

It is a further object to provide .an optionally automatic dog release mechanism, actuated by .movement vof the carriage.

The novel features .of this invention, together with still further objects and advantages thereof, will become more readily apparent when considered in connection with the accompanying drawings, in which:

Fig. l is a view in elevation of the improved sawmill according to this invention;

Fig. 2 is a view in elevation and on a larger scale of the dog operating mechanism of this invention; and

Figs. 3 and 4 are sectional views on a still larger scale taken on lines 3.3 and 44, respectively, 30f Fig. 2.

Referring now to the drawings, wherein like elements are designated by the same reference characters, and more particularly to Fig. 1, it is seen that the improved sawmill of this invention comprises .a base structure 11, including a sawyers pit -12 and -a takeaway mans pit 13. Supported by base structure 11, is aytrack 14 whereon a carriage 15 is mounted for transporting a log 16. Log 16 is held in place on carriage 15 by a dog 17 which may be raised and lowered by a hand Wheel 18 and a fly wheel 19 rotatable therewith. Also included in the improved sawmill of this invention :are circular vsaw blades 21, 22, (driven by conventional means not shown) and an overhead structure 23, including horizontal members 24 and 25, to which are aflixed a dog ICC release mechanism, designated generally by the numeral 26. Release mechanism 26 is provided with :a take away mans stirrup 27 and a sawyers pedal 28 for the control thereof by either of two operators, the take away man, and the sawyer, respectively.

The manner in which the releasing action of mechanism 26 is initiated by stirrup 27 and pedal 28 will be more readily apparent by reference to Figs. 2 and 3, wherein mechanism 26 is shown in detail. Referring 0 now to Figs. 2 and 3, it is seen that stirrup 27 is pivotally connected through a pull rod 29 to a control arm 31, the latter being fixed to a rotatable control shaft 32. Shaft 32 is journaled in suitable bearings 33 .and suspended horizontally from overhead members 25 by means of bearing mounts 34. To prevent ,sidewise motion of control arm 31, and to limit its arcuate travel, control arm 31 projects through a slotted bar or guide 35, and is tensioned by a spring 36.

Also fixed to shaft 32 is a counterweight 37 and an operating arm 38, the latter having at its end remote from shaft 32 a collar assembly 39 in slidable engagement with a connecting rod 41. On one side of collar assembly 39 toward the right of Fig. 2, connecting rod 41 'is provided with a stop, not shown, for restricting the travel of collar assembly 39 towards .the right. On the other side of collar assembly 39 toward the left of Fig. 2, there is provided a compression spring 42 concentric with connecting rod 41 and retained thereon by nut 43. Rod 41 is pivotally connected to a .runner 44 suspended from overhead member 24 by means of pivot arms 45. Finally a switch arm 46 is attached to runner 44 for operating a signal bell 47.

For control of operating mechanism 26 by pedal 28, there is provided a .control cable 48 which is connected to pedal 28 at one of its ends, passed over .a pulley 49, and attached to a control rod 51, as shown in Figs. 11 and 2. As shown in Fig. 2, control rod 51 is pivotally connected to a control arm 53 which in turn is joined to shaft 32. For tensioning control rod 5'1, there is provided a spring 54 connected to a bracket 55..

Referring now to Fig. 4, it may be noted that the undersurface of runner 44 is composed of rubber ortsome other suitable material having a relatively high coeflicient of friction. This 'is because runner'44, when lowered sufficiently, is adapted to engage the periphery of hand wheel 18, causing it to rotate counterclockwise, thereby releasing dog 17 as carriage 15 moves forward or toward the right. More particularly, the drive mechanism ,for releasing dog 107 with counterclockwise rotation of hand wheel 18 comprises a housing formed in two sections, 61 and 62. When bolted together, housing sections 61 and 62 have mating holes through which .an auxiliary drive shaft 63 and bushing 64 are inserted. Shaft 63 is provided with a thrust bearing 65 held in place by jam nuts 66. Fly wheel 1.9 is coupled to shaft .63 adjacent jam nuts '66, the end of shaft 63 being provided with a nut 67. Keyed to the opposite end of shaft .63 is .a bevel gear 68, partially .enclosed by an end shield 69 :on housing section 62. Hand wheel 18 is secured to the hub of bevel gear 63 adjacent end shield 69. A washer 71 and a nut 72011 shaft 63 retain hand wheel 18 on the hub of bevel gear 68.

:Housing section 61 also includes a vertical hole provided with a bushing 73, for receiving a main drive shaft '74 and an attached bevel gear 75. As shown in Fig. 4, the teeth-of bevel gear "75 are in mesh with bevel gear 68 and the hub of bevel gear 75 bears on bushing 73. A thrust bearing '76 and a bearing housing '77, bolted to housing-section 61, support bevel geariS int-his position. As will be apparent to those skilled in the art, the remainder of the drive mechanism, including a screw 81 coupled to shaft '74, is relatively conventional. That is to say, screw 81 cooperates with a threaded frame casting or nut 82, to which dog 17 is aflixed.

In operation, log 16 may be readily secured to carriage 15 by dog 17 with a single downward pull of hand wheel 18. This is because the energy supplied to hand wheel 18 in this manner is transmitted through auxiliary drive shaft 63 to fly wheel 19 so as to maintain shaft 63 in rotation. Since main drive shaft 74 is geared to shaft 63 by bevel gears 68 and 75, it too is caused to rotate an amount sufficient to lower dog 17 into a position of firm engagement with log 16. Of course a reverse pull on hand wheel 18 will cause shaft 74 to rotate in the opposite direction, thereby raising dog 17 after the boards have been cut from the log.

Alternatively, dog 17 may be automatically released either by depressing pedal 28, or lowering stirrup 27. In the former case, the downward force on pedal 28 is translated into a horizontal force on control rod 51 by means of cable 48 and pulley 49, with the result that rod 51 is drawn toward the left under tension of spring 54. Control arm 53, which is pivotally connected to rod 51 is thereby caused to rotate clockwise, as is shaft 32 and operating arm 38. As a result, spring 42 is compressed against nut 43, so that a horizontal force is applied to connecting rod 41. By means of this force, the runner 44, which is pivotally attached to rod 41 and overhead member 25, is swung toward the left and downward into a position of engagement with hand wheel 18. A downward pull on stirrup 27 will also cause runner 44 to be lowered into position by virtue of the moment applied to shaft 32 through control arm 31 and pull rod 29. In either case, the position of runner 44 will always be known to the operators, since switch arm 46 is adapted to actuate signal bell 47 whenever runner 44 is lowered. Thus, when the carriage 15 reaches a position near the end of its run with the hand wheel 18 beneath the runner 44, if the latter is moved to its lower position, the hand wheel 18 will be rotated in counterclockwise direction, as indicated in Fig. 2, thus raising the dog 17 and automatically releasing the remaining portion of the log 16.

While I have herein disclosed and described a presently preferred embodiment of the invention, it is nevertheless understood that the same is susceptible of numerous modifications and changes which will occur to those skilled in the art.

I claim:

1. In a sawmill having a movable carriage on which is mounted a dog and a screw mechanism for raising and lowering said dog, the combination with said screw mechanism of a main drive shaft coupled to said screw mechanism; an auxiliary drive shaft, the axis of said auxiliary drive shaft being oriented horizontally and at right angles to the direction of travel of said carriage; a gear train coupling said auxiliary drive shaft to said main drive shaft; a hand wheel rotatable with said auxiliary drive shaft; a pivotally suspended runner positioned parallel to the direction of travel of said carriage and at a height slightly greater than the height of the uppermost peripheral extremity of said hand wheel; a rotatably mounted control shaft; an operating arm fixed to said control shaft; a connecting rod pivotally connected to said runner and in semi-slidable engagement with said control arm; and means for rotating said control shaft to reposition said runner, said runner engaging the periphery of said hand wheel, so that movement of said carriage causes said hand wheel to rotate and said dog to be raised.

2. The combination according to claim 1, wherein said operating means includes a first control arm; and a control rod pivotally connected to said first control arm.

3. The combination according to claim 2, wherein said operating means includes a cable attached to said first control rod and a foot pedal connected to said cable for remotely controlling the position of said runner.

4. The combination according to claim 3, wherein said operating means includes a second control arm fixed to said control shaft, and a stirrup pivotally connected to said second control arm for controlling the position of said runner.

5. In a sawmill having a movable carriage on which is mounted a dog, and a screw mechanism for raising and lowering said dog, the combination with said screw mechanism of a vertically disposed main drive shaft coupled to said screw mechanism; an auxiliary drive shaft oriented at right angles to said main drive shaft and to the direction of travel of said carriage; a pair of bevel gears coupling said auxiliary drive shaft to said main drive shaft; a hand wheel fixed to one end of said auxiliary drive shaft; a fly wheel fixed to the other end of said auxiliary drive shaft; a pivotally suspended runner positioned parallel to the direction of travel of said carriage and at a height slightly greater than the height of the uppermost peripheral extremity of said hand wheel; a rotatably mounted control shaft; an operating arm fixed to said control shaft; a connecting rod pivotally connected to said runner and in semi-slidable engagement with said control arm; first and second control arms fixed to said control shaft; adjacent said operating arm; a foot pedal; a cable connected between said foot pedal and said first control arm; and a stirrup pivotally connected to said second control arm.

6. In a sawmill having a movable carriage on which is mounted a dog, and a screw mechanism for raising and lowering said dog, the combination with said screw mechanism of a main drive shaft coupled to said screw mechanism; an auxiliary drive shaft, the axis of said auxiliary drive shaft being oriented horizontally and at right angles to the direction of travel of said carriage; a gear train coupling said auxiliary drive shaft to said main drive shaft; a hand wheel aflixed to said auxiliary drive shaft, said wheel being disposed in a vertical plane on the same side of said carriage as said dog and sufficiently close to the center of said carriage to permit the hand wheel to clear the saw, said wheel being adapted to engage an overhead runner for automatically operating the dog as the carriage moves beneath the runner.

7. In a sawmill having a movable carriage on which is mounted a dog, and a screw mechanism for raising and lowering said dog, the combination with said screw mechanism of a main drive shaft coupled to said screw mechanism; an auxiliary drive shaft, the axis of said auxiliary drive shaft being oriented horizontally and at right angles to the direction of travel of said carriage; a gear train coupling said auxiliary drive shaft to said main drive shaft; a hand wheel affixed to said auxiliary drive shaft, said wheel being disposed in a vertical plane on the same side of said carriage as said dog and sufficiently close to the center of said carriage to permit the hand wheel to clear the saw, an overhead runner oriented parallel to the direction of travel of said carriage; mountings for said runner including a mechanism for lowering the runner to engage the periphery of said hand wheel and for raising the runner out of engagement therewith; and a control mechanism associated with said runner to control the up and down movement thereof.

References Cited in the file of this patent UNITED STATES PATENTS Tufts Feb. {28, 1933 

